Connecting sheath for conductor bar assemblies



Aug. 1, 1961 D. H. SCOFIELD ETAL 2,994,734

CONNECTING SHEATH FOR CONDUCTOR BAR ASSEMBLIES Filed Dec. 31, 1959 2o 4 swLww INVENTOR flO/VALD H Scams/.0 NE/L A. CLUMPNER A'ITORNEY5 2,994,734 CONNECTING SHEATH FOR CONDUCTOR BAR ASSEMBLIES Donald H. Scofield, Redwood City, and Neil A. Clumpner, San Mateo, Calif., assignors to Insul-8-Corp., San

Carlos, 'Calif., a corporation of California Filed Dec. 31, 1959, Ser. No. 863,139 1 Claim. (Cl. 174-92) This invention relates broadly to systems for supplying electric energy from a fixed conductor bar to a moving vehicle such, for example, as a traveling crane or hoist, an elevator, or the like.

In systems of the described type a conductor bar is mounted adjacent and parallel to the track on which the vehicle travels, and this bar is engaged by a current collecting shoe carried by a trolley which is mounted on the vehicle. In usual practice at this time the conductor bar is 8-shaped in cross section, having two spaced parts of circular cross section connected by a flat web part and such bars are formed of bent sheet metal, in which case the spaced circular parts will be hollow, or are cast or extruded, in which case the circular parts will be solid. All bars now in commercial use, and to which the present invention relates, are formed as elongated pieces or sections, each of which is provided with a separate insulating sheath extending throughout the entire, or substantially the entire, length of the bar. Said sheaths are formed of electrically insulating material and closely surround substantially the entire periphery of the bar, leaving only an exposed surface of one of the circular parts of the bar which may be engaged by the sliding collector shoe carried by the trolley mounted on the moving vehicle.

It is often necessary to position such conductor bars in end-to-end relation in order to provide electric power to a track of longer length than the usual commercial length of conductor bar. In such installations the insulating sheath associated with each conductor bar is terminated short of the end of the bar in order to leave an uncovered end section of each bar which may be used in connecting two bars by forcing their aligned hollow circular parts onto connecting pins, in the manner and preferably with the means disclosed in the co-pending application of Alleyne C. Howell, Jr., Serial No. 494,385, filed March 15, 1955, for Connector for Electrical Conductor. It will be apparent that after the ends of the two aligned bars have been connected in this manner a gap will be left between the ends of the insulating sheaths associated with the two bars, and it has been the practice to fill this gap and cover the exposed parts of the two bars with a short length of insulating sheath which extends between the spaced ends of the longer lengths of insulating sheath associated with the two conductor bars. It has been found that such known means for covering the exposed end parts of the conductor bars between the ends of the sheaths associated with such bars are not satisfactory because shrinkage of the longer lengths of sheath due to elevated ambient temperature conditions causes the sheaths, which are usually made of a synthetic plastic material, to shrink or contract in length, thus exposing parts of the conductor bars.

The present invention has to do with conductor bar and sheath assemblies of the described type and has for its principal object the provision of means for covering the exposed ends of aligned and connected conductor bars, outside of and between the ends of the insulating sheaths associated therewith, which means will not be subject to the disadvantage described above which results from shrinkage of the insulating sheaths at high ambient temperatures.

The invention is described in the following specificanited States Patent M Patented Aug. 1, 1961 tion and is illustrated in the accompanying drawing, in which:

FIG. 1 is a side elevational view showing an assembly of two aligned and connected conductor bars, the insulating sheaths associated with them, and the new and improved means provided by the present invention for covering the exposed ends of the conductor bars;

FIG. 2 is a bottom plan view of the parts and members shown in FIG. 1;

FIG. 3 is a view which is similar to FIG. 1, showing the bridging member provided by the present invention in position to be assembled to the conductor bars and insulating sheaths, and

FIG. 4 is a sectional view taken on line 44 of FIG. 1.

It is now known, and the usual practice, to provide a cover for the exposed ends of two aligned and connected conductor bars, each of which is covered and partially surrounded by an insulating sheath which stops short of the end of the bar, at the end thereof which is connected to the other bar. Such an assembly of parts is conventional in the art and is shown in the drawings and comprises the two aligned conductor bars 2, 4 which are connected at their ends to form a longer length of bar. Each bar is preferably S-shaped in cross-section, as shown in FIG. 4, and has spaced parts 6, 8 of circular cross-section integrally connected by a flat web part 10. The conductor bars may be solid or, preferably, may be formed by bending sheet metal into the described shape, in which case the two spaced circular parts 6, 8 of each bar will be hollow and the two bars may be connected by pins 12, 14 which extend tightly into the two hollow parts 6, S of the two bars.

Each of the two conductor bars is partially enclosed throughout substantially its entire length by an insulating sheath, the two sheaths being shown at 20, 22 in the drawing. Each sheath is U-shaped in cross section, as shown in FIG. 4, and surrounds and covers substantially the entire exterior surface of its associated conductor bar, leaving exposed only one surface of one of the spaced circular parts 6, 8 of the bar which may be engaged by the sliding collector shoe of a movable trolley. In accordance with known practice the insulating sheath associated with each conductor bar does not extend to the end of the bar With which it is associated but, as shown in the drawings, stops short of such end in order to permit the adjacent exposed ends of the two conductor bars to be engaged by a tool in order to force the end parts of the circular parts 6, 8 of the bars onto the connecting pins 12, 14. It has heretofore been the practice to cover the exposed ends of the two conductor bars by means of a short length of insulating sheath which is slipped over the two exposed ends of the conductor bars between the spaced ends of the insulating sheaths. Such a means of covering the exposed ends of the conductor oars has the disadvantages described above.

Means are provided by the present invention for covering the exposed parts of adjacent ends of two aligned and connected bars in a new and improved manner, Such means comprise a piece of insulating sheath having generally the same, but larger, cross sectional shape as that of the insulating sheaths which surround the two lengths of conductor bar, but which is of such length that at each of its ends it extends over and covers an end of one of the insulating sheaths, thereby not only bridging the space between the ends of the two sheaths and covering the exposed ends of the two conductor bars but also covering the spaced end parts of the two sheaths. A device as provided by this invention is shown at 30 in the drawings and comprises a piece of insulating sheath having the same cross sectional shape as that of the sheaths 20, 22 but being larger in all cross-sectional dimensions so that it may be slipped over the outsides of the sheaths. The device 30 is also specially formed in accordance with the invention to be of substantially grater length than the gap 32 between the spaced ends of the sheaths 20, 22. It will be seen that because of the generally flexible nature of the synthetic plastic material from which the bridging device and insulating sheaths are formed the bridging device may be snapped over the two end parts of the sheaths 20, 22-, in which position a substantial length of the end part of each of sheaths 20, 22 will be covered by the end parts of the bridging device. Because of this overlapping of substantial lengths of the bridging member and the two sheaths 20, 22 either or both of the sheaths 20, 22 may'shrink in length because of high ambient temperature-conditions, or for any other reason, without causing exposure of any part of the conductor bar, which will continue to be covered by the bridging member.

Means are provided by the bridging device of the invention for facilitating the guidance of the current-collecting shoe of the trolley as it moves from one insulating sheath to another. Such means comprise inwardly directed beads 40, 42 which extend inwardly from the spaced free edges 44, 46 of the bridging member 30 at and adjacent the midpoint of the length thereof. These beads are of the same length and their length is equal to that of the space 32 between the ends of the insulating sheaths 20, 22. As pointed out above, the bridging member 30 has the same general cross-sectional shape as that of the two insulating sheaths but is somewhat larger in all dimensions of this cross-section than the two insulating sheaths in order to permit it to be slipped over the outside surface of the sheaths. The spaced free edges 44, 46 of the bridging member are therefore spaced farther apart than the corresponding free edges 48, 50 of the insulating sheaths and the beads 40, 42 therefore bridge the gap between the ends of the free edges 48, 50 of the two insulating sheaths to provide continuous edges engaging the sides of the current collecting shoe of the trolley moving between the edges of the insulating sheaths.

While I have described and illustrated one form which the invention may take, it will be apparent to those skilled in the art that other embodiments, as well as modifications of that disclosed, may be made and practiced without departing in any way from the spirit or scope of the invention, for the limits of which reference must be made to the appended claim.

What is claimed is:

A device for covering the adjacent exposed ends of two aligned conductor bars which are joined in end-toend relation and each of which has a U-shaped insulating sheath substantially surrounding it throughout substantially its entire length and stopping short of its end to leave an end part of the conductor bar exposed, said device comprising an insulating sheath which is U-shaped in cross section and having larger cross-sectional dimensions than the insulating sheaths on the conductor bar and closely positioned on the exterior surfaces of the insulating sheaths in tightly surrounding relation thereto, the free edges of all said U-shaped members being aligned toperrnit free access to the bars, said device also being relatively short in length with respect to either of the insulating sheaths on the conductor bars and of substantially greater length than the distance between the ends of the insulating sheaths on the conductor bars to bridge the space between the ends of the insulating sheaths and cover a substantial part of the end of each of the insulating sheaths on the conductor bars, said U-shaped device having beads extending inwardly from the free edges thereof, intermediate the respective ends of said device, at and adjacent the midpoints thereof, the ends of said beads fitting into the space between the ends of the insulating sheaths to provide a continuous edge surface.

References Cited in the file of this patent UNITED STATES PATENTS 856,385 Baker June 11, 1907 1,813,200 Rogers July 7, 1931 2,267,630 Weiland Dec. 23, 1941 2,356,006 Sammer Aug. 14, 1944 2,803,696 Hefner Aug. 20, 1957 2,924,674 Taylor Feb. 9, 1960 OTHER REFERENCES Get Sound Bus Joints the Easy Way, published in Electrical World, Dec. 29, 1952 (page 9.1 relied on). 

